Sunscreen ingredient kills cells

Related Stories

A substance found in 90 per cent of sunscreens around the world has been shown to kill animal cells.

New Scientist reports Norwegian scientists have discovered that octyl methoxycinnamate (OMC) may also become deadly after a few hours in the sun.

Researchers at the Norwegian Radiation Protection Authority added OMC at a concentration of five parts per million to mouse cells suspended in ethyl alcohol, and found that only half survived, compared to 90 per cent in a control group without OMC. The concentration of OMC was far lower than that found in sunscreens.

When a light was shone on the OMC-soaked cells, simulating sunshine, even more died. This, researchers suggested, was because the products of reaction between OMC and light are more toxic than OMC alone.

Researcher, Terje Christensen told New Scientist he believed OMC could damage human cells if it penetrated the outer layer of dead cells: sunscreens, he said, should only be used when other protective measures cannot.

But the experiment is far from realistic, according to Professor of Dermatology Chris Anderson from Liverpool Hospital in Sydney. "It's a very artificial experiment, and it's always difficult to extrapolate from an in vitro experiment using mouse cells, to a live human situation," he said.

How then to explain the cell mortality? "We are still very unaware of the photoprotection mechanisms that go on inside the cell," he said. "It may be that OMC and alcohol are a bad combination, that affect the cell itself."

Professor Anderson said behavioural change should be the first line of defence against skin cancer (such as getting out of the sun when it is hottest), with sunscreens used if and when necessary.